Ultrathin electronic packages typically require stiffening in order to reduce temperature-related warpage during ball attach processes and/or solder mounting processes. One common technique for reducing temperature-related warpage is to attach a stiffener to a substrate around a die that is on the substrate.
A thicker stiffener provides better warpage control. However, a thicker stiffener also increases stress on the die making it prone to cracking. A thicker stiffener also makes it more difficult to fabricate the electronic packages that include such stiffeners. This is especially true where fabrication processes utilize tools which come close to the substrate during high speed manufacturing operations (e.g., underfill processes).
Another problem with conventional solutions relating to the temperature-related warpage of electronic packages is many solutions might improve temperature-related warpage at either lower temperatures or high temperatures, but do not improve temperature-related at both low and high temperature. Low temperature warpage reduction is needed for post-die attach processes since the electronic package tends to warp after the electronic package is cooled down after attaching the die to a substrate. In addition, high temperature warpage reduction is typically needed during solder mounting processes where the electronic package is attached to a panel (e.g., a printed circuit board) such that there are no openings or shorts formed when the electronic package is attached to the panel.